Recently, with the development of science and technology, many opto-electronic/electronic devices are designed toward small size, light weightiness and easy portability. Consequently, these opto-electronic/electronic devices can be applied to mobile business, entertainment or leisure purposes whenever or wherever the users are. In these devices, function of image capturing has been a standard assignment and playing a basic functional unit. Indeed, various image capturing devices are widely used in many kinds of systems such as smart phones, tablet computers, wearable devices or any other appropriate electronic devices, modules, or systems. Since the image capturing devices are small and portable, the users can use the image capturing devices to take images and store the captured images according to the users' demands. Not less common, alternatively the images can be uploaded to the interne through mobile networks so as to implement data transfer.
On the other hand, sensing devices, such as global positioning system (GPS) sensor, environmental sensing senor, proximity sensor, and ambient light sensor, have been developed to give convenience and/or security to users and make system operations smoother and more efficient. However, with the maturity of the sensing devices and the image capturing devices, the overall structures are complicated and bulky. Therefore, it is important to integrate the image capturing devices and the sensing devices to achieve the miniaturization purpose. Meanwhile, because of size reeducation, the integration of common sensing element to typical imaging sensor, such as CMOS type, also may reduce the power consumption of typical sensing element and provide a continuous and simultaneous monitoring. However, in terms of lens optics, it means that we need to integrate two kinds of function, i.e., imaging optics and non-imaging optics, simultaneously in one optical element.
FIG. 1 is a schematic cross-sectional side view illustrating a conventional image taking device. As shown in FIG. 1, the conventional image capturing device 1 comprises an optical lens 11, an optical sensor 12 and a casing 13. The optical lens 11 comprises a piece of lens. The light L from an object located outside is introduced into the image capturing device 1 through the optical lens 11. The optical sensor 12 is aligned with the optical lens 11. After the light L is sensed by the optical sensor 12, a corresponding image signal is generated. Consequently, an image corresponding to the image signal is displayed on a display device (not shown) that is connected with the image capturing device 1. The optical lens 11 and the optical sensor 12 are accommodated and positioned within the casing 13. Subsequently, the optical lens 11 and the optical sensor 12 can be normally operated. Moreover, the casing 13 has an opening 11. The optical lens 11 is exposed outside through the opening 131, so that the light L is allowed to pass through the optical lens 11. The optical lens 11 has an optical axis A and a field angle θ, while the corresponding field of view (FOV) is 2θ. The viewing zone of the image capturing device 1 is determined according to the field angle θ. As shown in FIG. 1, the optical lens 11 is a circular lens with a diameter 2×R where R is the radius of the clear aperture. Generally, as the size of the optical lens 11 increases, the field angle θ increases and the viewing zone increases. Moreover, the size of the opening 131 is slightly larger than the effective optical size (or the clear aperture) of the optical lens 11. The illustration here is generally for the function of imaging optics.
If the optical sensor 12 of the image capturing device 1 is with a smaller size, the light L may not be introduced to the optical sensor 12 easily. For solving this problem, a light guide element (not shown) could be arranged between the optical lens 11 and the optical sensor 12 for guiding the light L to the optical sensor 12. Generally, if the field angle θ (or the corresponding FOV) is larger, the light L after passing through the optical lens 11 will have one intersection (which is denoted as “turning point” here) and the turning point will be closer to the optical lens 11. Under this circumstance, it is necessary to install a longer light guide element in order to guide the light L to the optical sensor 12 properly. However, a longer light guide element has impaired guiding efficiency and higher cost, and the arrangement of the longer light guide element also increases the length of the casing 13. It should be noted that in many cases, the introduction of light guiding element make light collection efficiently, and hence the implementation of light guiding element is for the function of non-imaging optics mainly.
In current markets, the conventional image capturing device has two demands required to be matched critically. Firstly, both of the higher FOV and the smaller casing length (or, total track length) should be taken into consideration. Secondly, with the proviso that the size of the optical apparatus is minimized, it is necessary to expand the functions of the optical apparatus and achieve the function of capturing images and monitoring light amount or different wavelengths.